I'm one of those guys who just won't buy merchandise even if it is from the show that they like unless it's really good, I guess you could say that I'm a money-saving guy. As for the merchandise there are shirts, posters, gundam models, figurines, mask (i only saw AoT titan masks but they sold much more masks) and some stuff i didn't see, there is nothing that catches my eyes.
I would buy just to give back to the makers since I illegally stream and torrent their stuff. I can't buy figures or posters though since if I displayed them I'd get my ass kicked. I want to start a big blu-ray disc collection of all my favorite shows though, but it's pretty expensive so I'd have to get a job first.